The present invention relates to improved bearing assemblies for flexible frame towed agricultural implements for use in cultivation and the like and in particular bearing assemblies for such implements incorporating cylindrical bearings formed from ultra high molecular weight polyethylene.
Flexible frame towed agricultural implements have been developed to permit cultivation of uneven terrain with wider implements. The flexible frame towed implements generally comprise a plurality of rigid frames pivotally secured together in side by side alignment transverse to the direction of travel of the towing vehicle with a tool or set of tools connected to each frame. A plurality of hinges connect adjacent frame members. Each hinge generally comprises a male hinge member extending from the side of a first frame and a female hinge member extending from the side of a second or adjacent frame. The hinge members are generally formed from square tubing and the male hinge tube has a bore extending through the front and rear walls thereof. An outer cylindrical bearing sleeve, formed of metal, is welded inside of the end of the first length of square tubing in alignment with the bores in the front and rear walls thereof. An inner cylindrical bearing sleeve, formed of metal, is positioned within the outer cylindrical bearing sleeve.
The female hinge member includes a hinge clevis welded to a distal end of a section of square tubing. The distal end of the male hinge member on the first frame extends between front and rear ears of the hinge clevis such that the bores in the front and rear walls of the male hinge member are aligned with bores in the front and rear ears of the hinge clevis. A pivot pin extends through the bores in the ears of the hinge clevis, the bores in the front and rear walls of the male hinge tube and through the inner cylindrical bearing sleeve such that the male and female hinge tubes pivot about the pivot pin and relative to one another.
A grease zerk is secured to the outer cylindrical bearing sleeve and accessible through the end of the male hinge tube. Grease is injected between the inner and outer cylindrical bearing sleeves through the grease zerk for lubrication and to reduce wear. The continuing need to grease the numerous sets of bearing sleeves in a large implement consumes a considerable amount of time. Even with routine greasing, the outer cylindrical bearing sleeve will experience wear due to the metal on metal contact with the inner cylindrical bearing sleeve, which may require replacement of the outer cylindrical bearing sleeve. Because the outer cylindrical bearing sleeve is generally welded to the male hinge tube, its replacement is generally difficult and time consuming.
In addition to wear on the cylindrical bearing sleeves, the forward advancement of the implement generally thrusts either the front or rear wall of the male hinge tube against the front or rear ear of the hinge clevis respectively causing wear therebetween. The wear between the respective clevis ear of the female hinge tube and the wall of the male hinge tube may result in the need for additional costly repairs. To extend the life of the implements, users will grease the bearing surfaces between the hinge clevis and the male hinge tube, which only adds to the time required for routine maintenance.
Coulter mounting assemblies on many implements also require considerable maintenance and are subject to wear. Coulters are typically mounted on a hub which is connected to a coulter arm having a cylindrical bearing sleeve mounted on an end of the coulter arm opposite the hub. The cylindrical bearing sleeve is pivotally secured to a coulter shaft which is secured to and depends from the implement frame in front of a tool. The cylindrical bearing sleeve pivots about the coulter shaft to permit rotation of the coulter as the implement frame makes a turn. The metal on metal contact between the cylindrical bearing sleeve and the coulter shaft results in wear which can be reduced by the application of grease therebetween. Although the grease reduces wear it does not eliminate it and often the cylindrical bearing sleeve along with the coulter shaft need to be replaced. Further, the multiple greasings necessary to avoid excessive wear further increase the time necessary for routine maintenance. There remains a need for improved towed flexible frame agricultural implements with reduced maintenance needs which also resist wear at hinge points.